Gut microbiota-derived short-chain fatty acids and colorectal cancer: Ready for clinical translation?

Host-Gut Microbiota Metabolic Interactions and Their Role in Precision Diagnosis and Treatment of Gastrointestinal Cancers

The critical role of the gut microbiome in gastrointestinal cancers is becoming increasingly clear. Imbalances in the gut microbial community, referred to as dysbiosis, are linked to increased risks for various forms of gastrointestinal cancers. Pathogens like Fusobacterium and Helicobacter pylori relate to the onset of esophageal and gastric cancers, respectively, while microbes such as Porphyromonas gingivalis and Clostridium species have been associated with a higher risk of pancreatic cancer. In colorectal cancer, bacteria such as Fusobacterium nucleatum are known to stimulate the growth of tumor cells and trigger cancer-promoting pathways. On the other hand, beneficial microbes like Bifidobacteria offer a protective effect, potentially inhibiting the development of gastrointestinal cancers. The potential for therapeutic interventions that manipulate the gut microbiome is substantial, including strategies to engineer anti-tumor metabolites and employ microbiota-based treatments. Despite the progress in understanding the influence of the microbiome on gastrointestinal cancers, significant challenges remain in identifying and understanding the precise contributions of specific microbial species and their metabolic products. This knowledge is essential for leveraging the role of the gut microbiome in the development of precise diagnostics and targeted therapies for gastrointestinal cancers.

Macrophage Migration Inhibitory Factor (MIF) Upregulates CXCR7 and Contributes to Chemotherapy Resistance in Colorectal Cancer

Colorectal cancer is one of the most common malignant tumors worldwide, with high incidence and mortality rates making it a focus of research. Chemotherapy is a primary treatment modality for colon cancer, but chemotherapy resistance severely impacts treatment efficacy. MIF has been found to promote tumor progression and resistance in various cancers. This study aims to investigate the role of MIF in chemotherapy resistance in colon cancer and its potential mechanisms, particularly through the upregulation of CXCR7 expression, affecting the metabolism and drug sensitivity of colon cancer cells. The expression levels of MIF in colon cancer tissues and its association with patient prognosis were evaluated by analyzing TCGA and HPA data. Subsequently, the expression levels of MIF in colon cancer cell lines and resistant cell lines were detected by qRT-PCR and immunohistochemistry, and the effect of MIF on oxaliplatin sensitivity was assessed. The impact of MIF on the metabolic activity of colon cancer cells was measured using a cellular energy metabolism analyzer. Further experiments explored the mechanism by which MIF affects the metabolic activity of colon cancer cells through the upregulation of CXCR7 expression, and the role of CTCF in regulating CXCR7 transcription was validated by silencing CTCF. Finally, the effect of MIF on drug sensitivity of colon cancer cells was verified in a mouse xenograft tumor model. In this study, we found that the expression of MIF in colon cancer tissues was significantly higher than in normal tissues, and high MIF expression was associated with poor prognosis in patients. The expression levels of MIF in resistant colon cancer cell lines were significantly higher than in parental cell lines, and MIF overexpression significantly increased the resistance of colon cancer cells to oxaliplatin. Conversely, silencing MIF significantly reduced the IC50 value of resistant cells and increased apoptosis. MIF overexpression significantly increased the ECAR and OCR levels of colon cancer cells, while MIF knockdown significantly reduced these metabolic indicators. Further studies indicated that MIF affects the metabolic activity of colon cancer cells by upregulating CXCR7 expression. CTCF binding peaks at the CXCR7 promoter region and luciferase activity assays indicated that CTCF regulates CXCR7 transcription, and silencing CTCF significantly enhanced the sensitivity of colon cancer cells to oxaliplatin. In vivo experiments in mice showed that MIF silencing combined with oxaliplatin treatment significantly inhibited tumor growth and increased the necrotic area of tumor tissues. In conclusion, this study reveals the crucial role of MIF in chemotherapy resistance in colon cancer through the upregulation of CXCR7 expression, with CTCF playing an important regulatory role in this process. Our findings provide new theoretical insights and potential therapeutic targets for overcoming chemotherapy resistance in colon cancer. Future research should further explore the roles of MIF and CXCR7 in other types of cancers and the potential of MIF and CXCR7 as therapeutic targets.

Integrated metagenomic and metabolomic analysis reveals distinctive stage-specific gut-microbiome-derived metabolites in intracranial aneurysms

OBJECTIVE

Our study aimed to explore the influence of gut microbiota and their metabolites on intracranial aneurysms (IA) progression and pinpoint-related metabolic biomarkers derived from the gut microbiome.

DESIGN

We recruited 358 patients with unruptured IA (UIA) and 161 with ruptured IA (RIA) from two distinct geographical regions for conducting an integrated analysis of plasma metabolomics and faecal metagenomics. Machine learning algorithms were employed to develop a classifier model, subsequently validated in an independent cohort. Mouse models of IA were established to verify the potential role of the specific metabolite identified.

RESULTS

Distinct shifts in taxonomic and functional profiles of gut microbiota and their related metabolites were observed in different IA stages. Notably, tryptophan metabolites, particularly indoxyl sulfate (IS), were significantly higher in plasma of RIA. Meanwhile, upregulated tryptophanase expression and indole-producing microbiota were observed in gut microbiome of RIA. A model harnessing gut-microbiome-derived tryptophan metabolites demonstrated remarkable efficacy in distinguishing RIA from UIA patients in the validation cohort (AUC=0.97). Gut microbiota depletion by antibiotics decreased plasma IS concentration, reduced IA formation and rupture in mice, and downregulated matrix metalloproteinase-9 expression in aneurysmal walls with elastin degradation reduction. Supplement of IS reversed the effect of gut microbiota depletion.

CONCLUSION

Our investigation highlights the potential of gut-microbiome-derived tryptophan metabolites as biomarkers for distinguishing RIA from UIA patients. The findings suggest a novel pathogenic role for gut-microbiome-derived IS in elastin degradation in the IA wall leading to the rupture of IA.

Role of short-chain fatty acids in host physiology

Short-chain fatty acids (SCFAs) are major metabolites produced by the gut microbiota through the fermentation of dietary fiber, and they have garnered significant attention due to their close association with host health. As important mediators between the gut microbiota and the host, SCFAs serve as energy substrates for intestinal epithelial cells and maintain homeostasis in host immune and energy metabolism by influencing host epigenetics, activating G protein-coupled receptors, and inhibiting pathogenic microbial infections. This review provides a comprehensive summary of SCFAs synthesis and metabolism and offering an overview of the latest research progress on their roles in protecting gut health, enhancing energy metabolism, mitigating diseases such as cancer, obesity, and diabetes, modulating the gut-brain axis and gut-lung axis, and promoting bone health.

Refining the relationship between gut microbiota and common hematologic malignancies: insights from a bidirectional Mendelian randomization study

Background

The relationship between gut microbiota and hematologic malignancies has attracted considerable attention. As research progresses, it has become increasingly clear that the composition of gut microbiota may influence the onset and progression of hematologic malignancies. However, our understanding of this association remains limited.

Methods

In our study, we classified gut microbiota into five groups based on information at the phylum, class, order, family, and genus levels. Subsequently, we obtained data related to common hematologic malignancies from the IEU Open GWAS project. We then employed a bidirectional Mendelian Randomization (MR) approach to determine whether there is a causal relationship between gut microbiota and hematologic malignancies. Additionally, we conducted bidirectional MR analyses to ascertain the directionality of this causal relationship.

Results

Through forward and reverse MR analyses, we found the risk of lymphoid leukemia was significantly associated with the abundance of phylum Cyanobacteria, order Methanobacteriales, class Methanobacteria, family Peptococcaceae, family Methanobacteriaceae, and genera Lachnospiraceae UCG010, Methanobrevibacter, Eubacterium brachy group, and Butyrivibrio. The risk of myeloid leukemia was significantly associated with the abundance of phylum Actinobacteria, phylum Firmicutes, order Bifidobacteriales, order Clostridiales, class Actinobacteria, class Gammaproteobacteria, class Clostridia, family Bifidobacteriaceae, and genera Fusicatenibacter, Eubacterium hallii group, Blautia, Collinsella, Ruminococcus gauvreauii group, and Bifidobacterium. The risk of Hodgkin lymphoma was significantly associated with the abundance of family Clostridiales vadinBB60 group, genus Peptococcus, and genus Ruminococcaceae UCG010. The risk of malignant plasma cell tumor was significantly associated with the abundance of genera Romboutsia and Eubacterium rectale group. The risk of diffuse large B-cell lymphoma was significantly associated with the abundance of genera Erysipelatoclostridium and Eubacterium coprostanoligenes group. The risk of mature T/NK cell lymphomas was significantly associated with the abundance of phylum Verrucomicrobia, genus Ruminococcaceae UCG013, genus Lachnoclostridium, and genus Eubacterium rectale group. Lastly, the risk of myeloproliferative neoplasms was significantly associated with the abundance of genus Coprococcus 3 and Eubacterium hallii group.

Conclusion

Our study provided new evidence for the causal relationship between gut microbiota and hematologic malignancies, offering novel insights and approaches for the prevention and treatment of these tumors.

Effects of the gut microbiota and its metabolite short-chain fatty acids on endometriosis

In recent years, a growing body of research has confirmed that the gut microbiota plays a major role in the maintenance of human health and disease. A gut microbiota imbalance can lead to the development of many diseases, such as pregnancy complications, adverse pregnancy outcomes, polycystic ovary syndrome, endometriosis, and cancer. Short-chain fatty acids are metabolites of specific intestinal bacteria and are crucial for maintaining intestinal homeostasis and regulating metabolism and immunity. Endometriosis is the result of cell proliferation, escape from immune surveillance, and invasive metastasis. There is a strong correlation between the anti-proliferative and anti-inflammatory effects of short-chain fatty acids produced by gut microbes and the development of endometriosis. Given that the mechanism of action of gut microbiota and Short-chain fatty acids in endometriosis remain unclear, this paper aims to provide a comprehensive review of the complex interactions between intestinal flora, short-chain fatty acids and endometriosis. In addition, we explored potential microbial-based treatment strategies for endometriosis, providing new insights into the future development of diagnostic tests and prevention and treatment methods for endometriosis.

The role of the gut microbiota in tumor, immunity, and immunotherapy

In recent years, with the deepening understanding of the gut microbiota, it has been recognized to play a significant role in the development and progression of diseases. Particularly in gastrointestinal tumors, the gut microbiota influences tumor growth by dysbiosis, release of bacterial toxins, and modulation of host signaling pathways and immune status. Immune checkpoint inhibitors (ICIs) have greatly improved cancer treatment efficacy by enhancing immune cell responses. Current clinical and preclinical studies have demonstrated that the gut microbiota and its metabolites can enhance the effectiveness of immunotherapy. Furthermore, certain gut microbiota can serve as biomarkers for predicting immunotherapy responses. Interventions targeting the gut microbiota for the treatment of gastrointestinal diseases, especially colorectal cancer (CRC), include fecal microbiota transplantation, probiotics, prebiotics, engineered bacteria, and dietary interventions. These approaches not only improve the efficacy of ICIs but also hold promise for enhancing immunotherapy outcomes. In this review, we primarily discuss the role of the gut microbiota and its metabolites in tumors, host immunity, and immunotherapy.

Butyrate inhibits the malignant biological behaviors of breast cancer cells by facilitating cuproptosis-associated gene expression

BACKGROUND

Butyrate is a common short-chain fatty acids (SCFA), and it has been demonstrated to regulate the development of breast cancer (BC), while the underlying mechanism is still unreported.

METHODS

Gas chromatography was used to measure the amounts of SCFA (acetate, propionate, and butyrate) in the feces. Cell viability was measured by the CCK-8 assay. The wound healing assay demonstrated cell migration, and the transwell assay demonstrated cell invasion. The levels of protein and gene were determined by western blot assay and RT-qPCR assay, respectively.

RESULTS

The levels of SCFA were lower in the faecal samples from BC patients compared to control samples. In cellular experiments, butyrate significantly suppressed the cell viability, migration and invasion of T47D in a dose-dependent manner. In animal experiments, butyrate effectively impeded the growth of BC tumors. Toll like receptor 4 (TLR4) was highly expressed in the tumors from BC patients. Butyrate inhibited the expression of TLR4. In addition, butyrate promoted the expression of cuproptosis-related genes including PDXK (pyridoxal kinase) and SLC25A28 (solute carrier family 25 member 28), which was lowly expressed in BC tumors. Importantly, overexpression of TLR4 can reverses the promotion of butyrate to PDXK and SLC25A28 expression and the prevention of butyrate to the malignant biological behaviors of T47D cells.

CONCLUSION

In summary, butyrate inhibits the development of BC by facilitating the expression of PDXK and SLC25A28 through inhibition of TLR4. Our investigation first identified a connection among butyrate, TLR4 and cuproptosis-related genes in BC progression. These findings may provide novel target for the treatment of BC.

The impact of pre-, pro- and synbiotics supplementation in colorectal cancer treatment: a systematic review

Introduction

The effectiveness of the supplementation of prebiotics, probiotics and synbiotics as a therapeutic approach in colorectal cancer (CRC) remains unclear. The aim of this systematic review is to critically examine the current scientific evidence on the impact of modulating the microbiota, through the use of prebiotics, probiotics and synbiotics, in patients diagnosed with CRC undergoing treatment, to determine the potential therapeutic use of this approach.

Methods

This systematic review was made according to the PRISMA 2020 guidelines. Inclusion criteria were randomized controlled trials (RCT) comparing the impact of pre-, pro-, or synbiotic supplementation with placebo or standard care in patients with CRC undergoing treatment. Exclusion criteria were non-human studies, non-RCTs, and studies in languages other than English or Portuguese. Six databases were consulted, namely, Cochrane Library, Pubmed, Scopus, Cinahl, MedicLatina and Web of Science until May of 2023. RAYYAN software was used to manage the search results and risk of bias was assessed according to the guidelines of the Cochrane Collaboration using the Rob 2.0 tool.

Results

Twenty-four RCTs met the inclusion criteria and were included in this review. Administration of pre-, pro-, or synbiotics improved surgical outcomes such as the incidence of infectious and non-infectious postoperative complications, return to normal gut function, hospital length of stay, and antibiotic usage. The supplementation of these microorganisms also alleviated some symptoms from chemotherapy and radiotherapy, mainly diarrhea. Evidence on the best approach in terms of types of strains, dosage and duration of intervention is still scarce.

Conclusions

Pre-, pro-, and synbiotics supplementation appears to be a beneficial therapeutic approach in CRC treatment to improve surgical outcomes and to alleviate side-effects such as treatment toxicity. More RCTs with larger sample sizes and less heterogeneity are needed to confirm these potential benefits and to determine the best strains, dosage, and duration of administration in each situation.

Systematic review registration

https://www.crd.york.ac.uk/prospero, identifier CRD42023413958.

Influence of Gut Microbiota-Mediated Immune Regulation on Response to Chemotherapy

The involvement of the gut microbiota in anti-cancer treatment has gained increasing attention. Alterations to the structure and function of the gut bacteria are important factors in the development of cancer as well as the efficacy of chemotherapy. Recent studies have confirmed that the gut microbiota and related metabolites influence the pharmacological activity of chemotherapeutic agents through interactions with the immune system. This review aims to summarize the current knowledge of how malignant tumor and chemotherapy affect the gut microbiota, how the gut microbiota regulates host immune response, and how interactions between the gut microbiota and host immune response influence the efficacy of chemotherapy. Recent advances in strategies for increasing the efficiency of chemotherapy based on the gut microbiota are also described. Deciphering the complex homeostasis maintained by the gut microbiota and host immunity provides a solid scientific basis for bacterial intervention in chemotherapy.

Multiple-matrix metabolomics analysis for the distinct detection of colorectal cancer and adenoma

OBJECTIVES

Although colorectal cancer (CRC) is the leading cause of cancer-related morbidity and mortality, current diagnostic tests for early-stage CRC and colorectal adenoma (CRA) are suboptimal. Therefore, there is an urgent need to explore less invasive screening procedures for CRC and CRA diagnosis.

METHODS

Untargeted gas chromatography-mass spectrometry (GC-MS) metabolic profiling approach was applied to identify candidate metabolites. We performed metabolomics profiling on plasma samples from 412 subjects including 200 CRC patients, 160 CRA patients and 52 normal controls (NC). Among these patients, 45 CRC patients, 152 CRA patients and 50 normal controls had their fecal samples tested simultaneously.

RESULTS

Differential metabolites were screened in the adenoma-carcinoma sequence. Three diagnostic models were further developed to identify cancer group, cancer stage, and cancer microsatellite status using those significant metabolites. The three-metabolite-only classifiers used to distinguish the cancer group always keeps the area under the receiver operating characteristic curve (AUC) greater than 0.7. The AUC performance of the classifiers applied to discriminate CRC stage is generally greater than 0.8, and the classifiers used to distinguish microsatellite status of CRC is greater than 0.9.

CONCLUSION

This finding highlights potential early-driver metabolites in CRA and early-stage CRC. We also find potential metabolic markers for discriminating the microsatellite state of CRC. Our study and diagnostic model have potential applications for non-invasive CRC and CRA detection.

Recent progresses in gut microbiome mediates obstructive sleep apnea-induced cardiovascular diseases

Obstructive sleep apnea (OSA) is a multifactorial sleep disorder with a high prevalence in the general population. OSA is associated with an increased risk of developing cardiovascular diseases (CVDs), particularly hypertension, and is linked to worse outcomes. Although the correlation between OSA and CVDs is firmly established, the mechanisms are poorly understood. Continuous positive airway pressure is primary treatment for OSA reducing cardiovascular risk effectively, while is limited by inadequate compliance. Moreover, alternative treatments for cardiovascular complications in OSA are currently not available. Recently, there has been considerable attention on the significant correlation between gut microbiome and pathophysiological changes in OSA. Furthermore, gut microbiome has a significant impact on the cardiovascular complications that arise from OSA. Nevertheless, a detailed understanding of this association is lacking. This review examines recent advancements to clarify the link between the gut microbiome, OSA, and OSA-related CVDs, with a specific focus on hypertension, and also explores potential health advantages of adjuvant therapy that targets the gut microbiome in OSA.

Molecular crosstalk between polyphenols and gut microbiota in cancer prevention

A growing body of evidence suggests that cancer remains a significant global health challenge, necessitating the development of novel therapeutic approaches. In recent years, the molecular crosstalk between polyphenols and gut microbiota has emerged as a promising pathway for cancer prevention. Polyphenols, abundant in many plant-based foods, possess diverse bioactive properties, including antioxidant, anti-inflammatory, and anticancer activities. The gut microbiota, a complex microbial community residing in the gastrointestinal tract, plays a crucial role in a host's health and disease risks. This review highlights cancer suppressive and oncogenic mechanisms of gut microbiota, the intricate interplay between gut microbiota modulation and polyphenol biotransformation, and the potential therapeutic implications of this interplay in cancer prevention. Furthermore, this review explores the molecular mechanisms underpinning the synergistic effects of polyphenols and the gut microbiota, such as modulation of signaling pathways and immune response and epigenetic modifications in animal and human studies. The current review also summarizes the challenges and future directions in this field, including the development of personalized approaches that consider interindividual variations in gut microbiota composition and function. Understanding the molecular crosstalk could offer new perspectives for the development of personalized cancer therapies targeting the polyphenol-gut axis. Future clinical trials are needed to validate the potential role of polyphenols and gut microbiota as innovative therapeutic strategies for cancer treatment.

Targeting the gut microbiota to enhance the antitumor efficacy and attenuate the toxicity of CAR-T cell therapy: a new hope?

Chimeric antigen receptor (CAR) -T cell therapy has achieved tremendous efficacy in the treatment of hematologic malignancies and represents a promising treatment regimen for cancer. Despite the striking response in patients with hematologic malignancies, most patients with solid tumors treated with CAR-T cells have a low response rate and experience major adverse effects, which indicates the need for biomarkers that can predict and improve clinical outcomes with future CAR-T cell treatments. Recently, the role of the gut microbiota in cancer therapy has been established, and growing evidence has suggested that gut microbiota signatures may be harnessed to personally predict therapeutic response or adverse effects in optimizing CAR-T cell therapy. In this review, we discuss current understanding of CAR-T cell therapy and the gut microbiota, and the interplay between the gut microbiota and CAR-T cell therapy. Above all, we highlight potential strategies and challenges in harnessing the gut microbiota as a predictor and modifier of CAR-T cell therapy efficacy while attenuating toxicity.

Prevalence and implications of pKs-positive Escherichia coli in colorectal cancer

Colorectal cancer (CRC) remains a significant global health concern, necessitating continuous investigation into its etiology and potential risk factors. Recent research has shed light on the potential role of pKs-positive Escherichia coli (pKs + E. coli) and colibactin in the development and progression of CRC. Therefore, this review aimed to provide an updated analysis of the prevalence and implications of pKs + E. coli in colorectal cancer. We conducted a literature review search in major scientific databases to identify relevant studies exploring the association between pKs + E. coli and CRC. The search strategy included studies published up to the present date, and articles were carefully selected based on predefined inclusion criteria. Thus, the present study encompasses scientific evidence from clinical and epidemiological studies supporting the presence of pKs + E. coli in CRC patients, demonstrating a consistent and significant association in multiple studies. Furthermore, we highlighted the potential mechanisms by which colibactin may promote tumorigenesis and cancer progression within the colorectal mucosa, including the production of genotoxic virulence factors. Additionally, we explored current diagnostic methods for detecting pKs + E. coli in clinical settings, emphasizing the importance of accurate identification. Moreover, we discussed future strategies that could utilize the presence of this strain as a biomarker for CRC diagnosis and treatment. In conclusion, this review consolidated existing evidence on the prevalence and implications of pKs + E. coli in colorectal cancer. The findings underscore the importance of further research to elucidate the precise mechanisms linking this strain to CRC pathogenesis and to explore its potential as a therapeutic target or diagnostic marker. Ultimately, a better understanding of the role of pKs + E. coli in CRC may pave the way for innovative strategies in CRC management and patient care.

Chronic Stress Dampens Lactobacillus Johnsonii-Mediated Tumor Suppression to Enhance Colorectal Cancer Progression

Colorectal cancer development and outcome are impacted by modifiable risk factors, including psychologic stress. The gut microbiota has also been shown to be linked to psychologic factors. Here, we found a marked deteriorative effect of chronic stress in multiple colorectal cancer models, including chemically induced (AOM/DSS), genetically engineered (APCmin/+), and xenograft tumor mouse models. RNA sequencing data from colon tissues revealed that expression of stemness-related genes was upregulated in the stressed colorectal cancer group by activated β-catenin signaling, which was further confirmed by results from ex vivo organoid analyses as well as in vitro and in vivo cell tumorigenicity assays. 16S rRNA sequencing of the gut microbiota showed that chronic stress disrupted gut microbes, and antibiotic treatment and fecal microbiota transplantation abolished the stimulatory effects of chronic stress on colorectal cancer progression. Stressed colorectal cancer mice displayed a significant decrease in Lactobacillus johnsonii (L. johnsonii) abundance, which was inversely correlated with tumor load. Moreover, protocatechuic acid (PCA) was identified as a beneficial metabolite produced by L. johnsonii based on metabolome sequencing and LC/MS-MS analysis. Replenishment of L. johnsonii or PCA blocked chronic stress-induced colorectal cancer progression by decreasing β-catenin expression. Furthermore, PCA activated the cGMP pathway, and the cGMP agonist sildenafil abolished the effects of chronic stress on colorectal cancer. Altogether, these data identify that stress impacts the gut microbiome to support colorectal cancer progression.

SIGNIFICANCE

Chronic stress stimulates cancer stemness by reducing the intestinal abundance of L. johnsonii and its metabolite PCA to enhance β-catenin signaling, forming a basis for potential strategies to circumvent stress-induced cancer aggressiveness. See related commentary by McCollum and Shah, p. 645.

Analysis of differences in intestinal flora associated with different BMI status in colorectal cancer patients

BACKGROUND

Overweight is known to be an important risk factor for colorectal cancer (CRC), and the differences in intestinal flora among CRC patients with different BMI status have not been clearly defined. The purpose of this study was to elucidate the differences in the abundance, composition and biological function of intestinal flora in CRC patients with different BMI status.

METHOD

A total of 170 CRC patients were included and grouped according to the BMI data of CRC patients. BMI ≥ 24 kg/m2 was defined as overweight group, and BMI within the range of 18.5-23.9 kg/m2 was defined as normal weight group. Preoperative stool collection of patients in both groups was used for 16S rRNA sequencing. Total RNA was extracted from 17 CRC tumor tissue samples for transcriptome sequencing, and then CIBERSORT algorithm was used to convert the transcriptome data into the relative content matrix of 22 kinds of immune cells, and the correlation between different intestinal flora and immune cells and immune-related genes under different BMI states was analyzed. Finally, we identified BMI-related differential functional pathways and analyzed the correlation between these pathways and differential intestinal flora.

RESULT

There was no significant difference in α diversity and β diversity analysis between overweight group and normal weight group. Partial least square discriminant analysis (PLS-DA) could divide the flora into two different clusters according to BMI stratification. A total of 33 BMI-related differential flora were identified by linear discriminant effect size analysis (LEfSe), among which Actinomyces, Desulfovibrio and Bacteroides were significantly enriched in overweight group. ko00514: Other types of O-glycan biosynthesis are significantly enriched in overweight group. There was a significant positive correlation between Clostridium IV and Macrophages M2 and T cells regulatory (Tregs). There was a significant negative correlation with Dendritic cells activated and T cells CD4 memory activated.

CONCLUSIONS

The richness and diversity of intestinal flora of CRC patients may be related to different BMI status, and the enrichment of Actinomyces, Desulphurvibrio and Bacteroides may be related to overweight status of CRC patients. The tumor microenvironment in which BMI-related differential flora resides has different immune landscapes, suggesting that some intestinal flora may affect the biological process of CRC by regulating immune cell infiltration and immune gene expression, but further experiments are needed to confirm this.

Gut microbiota and its metabolites in non-small cell lung cancer and brain metastasis: from alteration to potential microbial markers and drug targets

Background

The elevated mortality rate associated with non-small-cell lung cancer (NSCLC) is a well-established global concern. Considerable attention has been directed toward exploring the association between gut microbiota and various malignant tumors. We herein investigated the associations between the intestinal microbiome and its metabolites, particularly short-chain fatty acids (SCFAs), in patients with NSCLC at different stages, including early and brain metastasis (BM) stages. The findings aim to offer a fresh perspective on the diagnosis and management of NSCLC.

Methods

Fecal samples were collected from 115 participants, comprising healthy controls (n = 35) and patients with treatment-naive NSCLC at the early stage (ELC, n = 40) and the BM stage (n = 40). Characterization of the intestinal microbiome and fecal SCFA levels was performed using 16S rRNA gene sequencing and gas chromatography.

Results

The microbial diversity in patients with NSCLC was found to be less abundant and uniform, particularly in the BM stage. Significant alterations in the community structure of the gut microbiota were observed in patients with NSCLC, with an increase in pathogens in Fusobacteria and Proteobacteria and a decrease in SCFA-producing bacteria in Firmicutes and Actinobacteria, particularly in the BM stage. Meanwhile, microbial communities displayed intricate associations in patients with NSCLC. A biomarker panel (Faecalibacterium, Bifidobacterium, Butyricicoccus, Klebsiella, Streptococcus, and Blautia) successfully distinguished patients in the ELC and BM stages from healthy controls (area under the curve: 0.884). The overall concentration of fecal SCFAs was significantly lower in patients with BM compared to patients with ELC and healthy controls. Subgroup analysis of acetate and butyrate yielded similar results. Moreover, multiple disrupted pathways in the NSCLC group were identified using the Kyoto Encyclopedia of Genes and Genomes annotation, including lipid metabolism and genetic information processing, specifically in the BM stage.

Conclusion

Compared with healthy controls, distinct host-microbe interactions were evident in different phases of patients with NSCLC. Furthermore, specific forms of the gut microbiome and SCFAs may serve as valuable biomarkers and therapeutic targets in the diagnosis and treatment of NSCLC.

Unlocking the potential of Rosa roxburghii Tratt polyphenol: a novel approach to treating acute lung injury from a perspective of the lung-gut axis

Introduction

Acute lung injury (ALI) is a serious respiratory disease characterized by progressive respiratory failure with high morbidity and mortality. It is becoming increasingly important to develop functional foods from polyphenol-rich medicinal and dietary plants in order to prevent or alleviate ALI by regulating intestinal microflora. Rosa roxburghii Tratt polyphenol (RRTP) has significant preventive and therapeutic effects on lipopolysaccharide-induced ALI mice, but its regulatory effects on gut homeostasis in ALI mice remains unclear.

Methods

This study aims to systematically evaluate the ameliorative effects of RRTP from the perspective of "lung-gut axis" on ALI mice by intestine histopathological assessment, oxidative stress indicators detection and short-chain fatty acids (SCFAs) production, and then explore the modulatory mechanisms of RRTP on intestinal homeostasis by metabolomics and gut microbiomics of cecal contents.

Results

The results showed that RRTP can synergistically exert anti-ALI efficacy by significantly ameliorating intestinal tissue damage, inhibiting oxidative stress, increasing SCFAs in cecal contents, regulating the composition and structure of intestinal flora, increasing Akkermansia muciniphila and modulating disordered intestinal endogenous metabolites.

Discussion

This study demonstrated that RRTP has significant advantages in adjuvant therapy of ALI, and systematically clarified its comprehensive improvement mechanism from a new perspective of "lung-gut axis", which provides a breakthrough for the food and healthcare industries to develop products from botanical functional herbs and foods to prevent or alleviate ALI by regulating intestinal flora.

Bacopaside I alleviates depressive-like behaviors by modulating the gut microbiome and host metabolism in CUMS-induced mice

Bacopaside I (BSI) is a natural compound that is difficult to absorb orally but has been shown to have antidepressant effects. The microbiota-gut-brain axis is involved in the development of depression through the peripheral nervous system, endocrine system, and immune system and may be a key factor in the effect of BSI. Therefore, this study aimed to investigate the potential mechanism of BSI in the treatment of depression via the microbiota-gut-brain axis and to validate it in a fecal microbiota transplantation model. The antidepressant effect of BSI was established in CUMS-induced mice using behavioral tests and measurement of changes in hypothalamicpituitaryadrenal (HPA) axis-related hormones. The improvement of stress-induced gut-brain axis damage by BSI was observed by histopathological sections and enzyme-linked immunosorbent assay (ELISA). 16 S rDNA sequencing analysis indicated that BSI could modulate the abundance of gut microbiota and increase the abundance of probiotic bacteria. We also observed an increase in short-chain fatty acids, particularly acetic acid. In addition, BSI could modulate the disruption of lipid metabolism induced by CUMS. Fecal microbiota transplantation further confirmed that disruption of the microbiota-gut-brain axis is closely associated with the development of depression, and that the microbiota regulated by BSI exerts a partial antidepressant effect. In conclusion, BSI exerts antidepressant effects by remodeling gut microbiota, specifically through the Lactobacillus and Streptococcus-acetic acid-neurotrophin signaling pathways. Furthermore, BSI can repair damage to the gut-brain axis, regulate HPA axis dysfunction, and maintain immune homeostasis.

Gut microbiota in cancer: insights on microbial metabolites and therapeutic strategies

In recent years, the role of gut microbiota in cancer treatment has attracted substantial attention. It is now well established that gut microbiota and its metabolites significantly contribute to the incidence, treatment, and prognosis of various cancers. This review provides a comprehensive review on the pivotal role of gut microbiota and their metabolites in cancer initiation and progression. Furthermore, it evaluates the impact of gut microbiota on the efficacy and associated side effects of anticancer therapies, including radiotherapy, chemotherapy, and immunotherapy, thus emphasizing the clinical importance of gut microbiota reconstitution in cancer treatment.

Isotope-Coded On-Tissue Derivatization for Quantitative Mass Spectrometry Imaging of Short-Chain Fatty Acids in Biological Tissues

Short-chain fatty acids (SCFAs), as the main metabolites of gut microbiota, are recognized as crucial players in the host's inflammatory response and metabolic disease. Imaging the spatial distributions and calculating the accurate contents of SCFAs in the heterogeneous intestinal tissue are critical to reveal their biological functions. Here, we develop an isotope-coded on-tissue derivatization method combined with matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to map the spatial expressions of SCFAs in the colon tissue based on pair-labeled N,N,N-trimethyl-2-(piperazin-1-yl)ethan-1-aminium iodide (TMPA) and D3-TMPA. A noticeable increase in the MALDI-MSI sensitivity of SCFAs was achieved after on-tissue derivatization, which enables the visualization of acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, hydroxy acetic acid, and hydroxy propionic acid in the colon tissue. Moreover, the introduction of D3-TMPA-tagged SCFAs as internal standards can significantly reduce quantitation deviation from the matrix effects, ensuring the quantitative MALDI-MSI of SCFAs. We further used this method to characterize the spatial alterations of SCFAs in the colon tissues of mice with enterocolitis. The development of this strategy provides a reliable approach to image the spatial expressions of SCFAs in tissues and paves an insight way to study the roles of SCFAs in the gut microbiota and disease.

The effects of race and probiotic supplementation on the intestinal microbiota of 10-km open-water swimmers

This study collected the stools of 10-km open-water swimmers after race and probiotic supplementation, and 16S rRNA sequencing and metabolomic analysis were performed to clarify their intestinal microbiota characteristics. The findings revealed a relatively high proportion of Firmicutes in all the athletes. Firmicutes in female athletes were significantly higher after probiotic supplementation. The intestinal microbiota of athletes was closely associated with the pathways of exercise against cancer, exercise against aging, exercise for improving cognition, sphingolipid metabolism and endocrine resistance. Future research should focus on the relationship between Firmicutes and Proteobacteria with super class metabolites in athletes. This report initially explored the changes in intestinal microbiota involved in metabolic pathways in athletes after race and after probiotic supplementation and provided a theoretical basis for the further improvement of the monitoring of their physical function after race and selection of nutritional strategies during exercise training.

Association between physical activity and the prevalence of tumorigenic bacteria in the gut microbiota of Japanese adults: a cross-sectional study

Escherichia coli harboring polyketide synthase (pks+ E. coli) has been suggested to contribute to colorectal cancer development. Physical activity is strongly associated with lower colorectal cancer risks, but its effects on pks+ E. coli remain unclear. The aim of this study was to investigate the association between pks+ E. coli prevalence and physical activity. A cross-sectional study was conducted on 222 Japanese adults (27-79-years-old, 73.9% female). Triaxial accelerometers were used to measure light-intensity physical activity, moderate-to-vigorous intensity physical activity, the physical activity level, step-count, and time spent inactive. Fecal samples collected from participants were used to determine the prevalence of pks+ E. coli. Multivariate logistic regression analysis and restricted cubic spline curves were used to examine the association between pks+ E. coli prevalence and physical activity. The prevalence of pks+ E. coli was 26.6% (59/222 participants). The adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the highest tertile with reference to the lowest tertile of physical activity variables were as follows: light-intensity physical activity (OR 0.63; 95% CI 0.26-1.5), moderate-to-vigorous intensity physical activity (OR 0.85; 95% CI 0.39-1.87), physical activity level (OR 0.69; 95% CI 0.32-1.51), step-count (OR 0.92; 95% CI 0.42-2.00) and time spent inactive (OR 1.30; 95% CI 0.58-2.93). No significant dose-response relationship was found between all physical activity variables and pks+ E. coli prevalence. Our findings did not suggest that physical activity has beneficial effects on the prevalence of pks+ E. coli. Longitudinal studies targeting a large population are needed to clarify this association.

Probiotic Pediococcus pentosaceus Li05 Improves Cholestasis through the FXR-SHP and FXR-FGF15 Pathways

Primary sclerosing cholangitis (PSC), a rare chronic cholestatic liver disease, is characterized by intrahepatic or extrahepatic strictures accompanied by biliary fibrosis. So far, there are no effective therapies to slow down the progression of this disease. Farnesoid X receptors (FXRs) are ligand-activated transcription factors involved in the control of bile acid (BA) synthesis and enterohepatic circulation. Therefore, targeting FXRs holds promise as a potential approach for treating PSC. Pediococcus pentosaceus Li05 is a probiotic that was isolated from healthy volunteers and has previously been shown to have an anti-inflammatory effect in DSS-induced colitis. In this study, we established a 3,5-diethoxycarbonyl-1,4-Dihydrocollidine (DDC)-induced cholestasis mouse model and investigated the effects of Pediococcus pentosaceus Li05 on PSC. Our findings revealed that administration of Li05 significantly attenuated liver damage, hepatic inflammation, and fibrosis, as well as bile duct hyperplasia. Li05 activated the hepatic FXR-SHP and ileal FXR-FGF15 signaling pathways to decrease the expression of Cyp7a1. In addition, the Li05-modulated gut microbiota structure especially improved the abundance of 7α-dehydroxylation bacteria like Eubacterium. The intervention of Li05 also improved the intestinal barrier and reduced bacterial endotoxin translocation. Based on these findings, Li05 shows promise for future application as a therapeutic strategy for cholestasis.

The metabolite butyrate produced by gut microbiota inhibits cachexia-associated skeletal muscle atrophy by regulating intestinal barrier function and macrophage polarization

OBJECTIVE

Cachexia, marked by muscle atrophy, poses substantial challenges for prevention and treatment. This study delves into the unclear role of butyrate, a gut microbiota metabolite, in cachexia by examining gut microbiota and short-chain fatty acid (SCFA) profiles in human and mouse fecal samples.

METHODS

We analyzed cachexia-associated gut microbiota and SCFA profiles using 16S rRNA sequencing and metabolomic techniques. Mouse cachexia models were developed with C26 cells, and LPS was used to induce muscle cell atrophy in C2C12 cells. We evaluated butyrate's in vivo effects on intestinal health, muscle preservation, inflammation, and macrophage activity. In vitro studies focused on butyrate's influence on macrophage polarization and the subsequent effects on muscle cells.

RESULTS

Both cachexia patients and mice exhibited gut microbiota imbalances, irregular butyrate concentrations, and a decline in butyrate-producing bacteria. In vivo tests showed that butyrate counteract cachexia-induced muscle atrophy by adjusting the Akt/mTOR/Foxo3a and Fbox32/Trim63 pathways. These butyrate also bolstered intestinal barrier integrity, minimized endotoxin migration, and mitigated oxidative stress. Furthermore, butyrate curtailed inflammation and macrophage penetration in muscles. In vitro experimental results demonstrate that butyrate inhibit macrophage polarization towards the M1 phenotype and promote polarization towards the M2 phenotype. Both M1 and M2 macrophages influence the aforementioned pathways and oxidative stress, participating in the regulation of muscle cell atrophy.

CONCLUSION

Our study delineates the intricate interplay between gut microbiota dysbiosis, butyrate fluctuations, and cachexia progression. Butyrate not only reinforces the intestinal barrier but also orchestrates macrophage polarization, mitigating muscle atrophy and averting cachexia-induced muscle deterioration. Concurrently, the M1 and M2 macrophages play pivotal roles in modulating skeletal muscle cell atrophy. This highlights the potential of utilizing the gut-derived metabolite butyrate as a promising therapeutic approach for addressing cachexia-related issues.

Isobutyric acid promotes colorectal cancer metastasis through activating RACK1

Colorectal cancer (CRC) metastasis plays a crucial role in disease progression, yet the regulatory mechanisms underlying metastasis remain incompletely understood. Isobutyric acid (IBA), a short-chain fatty acid found at high levels in serum of CRC patients, has been shown to be a critical metabolite influencing CRC proliferation. However, its role in tumor metastasis remains unknown. Here, utilizing liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis, we found that levels of IBA were significantly higher in patients with distant organ metastasis of CRC than in those without. Furthermore, IBA promoted CRC metastasis both in vitro and in vivo. Mass spectrometry, immunofluorescence, and cellular thermal shift assay revealed that IBA interacts with RACK1. Mechanistically, IBA binding to and activating RACK1 promotes regulation of downstream Akt and FAK signaling and CRC metastasis. Collectively, our study highlights the critical interplay between IBA and RACK1 and its impact on tumor metastasis. This study suggests that targeting the IBA-RACK1 signaling axis may be an effective therapeutic strategy for controlling CRC metastasis.

Effects of cereal bran consumption on cardiometabolic risk factors: A systematic review and meta-analysis

AIMS

Cardiovascular disease is a prevalent worldwide disease, and cardiometabolic risk factors (CMRFs) include hyperlipidemia, hypertension, diabetes, and adiposity. Healthy diets are the critical factor in controlling these CMRFs risks, especially cereal bran which contains many beneficial substances. However, there are still contradictions in the indicators of improving CMRFs by bran from different grain sources or even the same grain source. Therefore, this study aimed to investigate the effects of cereal bran consumption on CMRFs.

DATA SYNTHESIS

Eligible randomized controlled studies were searched in PubMed, Embase, Scopus, the Cochrane Library and Web of Science until February 2023. The random-effects model was used to calculate overall effect sizes of weighted mean difference (WMD) and 95% confidence interval (CI). Finally, 22 studies were included in the present meta-analysis. Compared to the control, cereal bran consumption had no significant effect on high-density lipoprotein cholesterol, triglycerides, waist circumference, and body mass index, but could reduce systolic blood pressure (WMD: -1.59; 95% CI: -2.45 to -0.72), diastolic blood pressure (WMD: -1.96; 95% CI: -3.89 to -0.04), total cholesterol (WMD: -0.19; 95% CI: -0.34 to -0.04), low-density lipoprotein cholesterol (WMD: -0.21; 95% CI: -0.38 to -0.04), and fasting blood glucose (WMD: -0.13; 95% CI: -0.24 to -0.01). Additionally, oat bran can lower blood lipids in individuals with lipid diseases and blood pressure in obese or hypertensive patients.

CONCLUSIONS

Cereal bran could significantly reduce blood pressure, total cholesterol, low-density lipoprotein cholesterol, and fasting blood glucose in individuals with CMRFs, and oat bran had the most obvious effect.

Organoid: Bridging the gap between basic research and clinical practice

Nowadays, the diagnosis and treatment system of malignant tumors has increasingly tended to be more precise and personalized while the existing tumor models are still unable to fully meet the needs of clinical practice. Notably, the emerging organoid platform has been proven to have huge potential in the field of basic-translational medicine, which is expected to promote a paradigm shift in personalized medicine. Here, given the unique advantages of organoid platform, we mainly explore the prominent role of organoid models in basic research and clinical practice from perspectives of tumor biology, tumorigenic microbes-host interaction, clinical decision-making, and regenerative strategy. In addition, we also put forward some practical suggestions on how to construct a new generation of organoid platform, which is destined to vigorously promote the reform of basic-translational medicine.

The Association between the Gut Microbiome and Development and Progression of Cancer Treatment Adverse Effects

Adverse effects are a common consequence of cytotoxic cancer treatments. Over the last two decades there have been significant advances in exploring the relationship between the gut microbiome and these adverse effects. Changes in the gut microbiome were shown in multiple clinical studies to be associated with the development of acute gastrointestinal adverse effects, including diarrhoea and mucositis. However, more recent studies showed that changes in the gut microbiome may also be associated with the long-term development of psychoneurological changes, cancer cachexia, and fatigue. Therefore, the aim of this review was to examine the literature to identify potential contributions and associations of the gut microbiome with the wide range of adverse effects from cytotoxic cancer treatments.

Intratumor microbiome derived glycolysis-lactate signatures depicts immune heterogeneity in lung adenocarcinoma by integration of microbiomic, transcriptomic, proteomic and single-cell data

Introduction

Microbiome plays roles in lung adenocarcinoma (LUAD) development and anti-tumor treatment efficacy. Aberrant glycolysis in tumor might promote lactate production that alter tumor microenvironment, affecting microbiome, cancer cells and immune cells. We aimed to construct intratumor microbiome score to predict prognosis of LUAD patients and thoroughly investigate glycolysis and lactate signature's association with LUAD immune cell infiltration.

Methods

The Cancer Genome Atlas-LUAD (TCGA-LUAD) microbiome data was downloaded from cBioPortal and analyzed to examine its association with overall survival to create a prognostic scoring model. Gene Set Enrichment Analysis (GSEA) was used to find each group's major mechanisms involved. Our study then investigated the glycolysis and lactate pattern in LUAD patients based on 19 genes, which were correlated with the tumor microenvironment (TME) phenotypes and immunotherapy outcomes. We developed a glycolysis-lactate risk score and signature to accurately predict TME phenotypes, prognosis, and response to immunotherapy.

Results

Using the univariate Cox regression analysis, the abundance of 38 genera were identified with prognostic values and a lung-resident microbial score (LMS) was then developed from the TCGA-LUAD-microbiome dataset. Glycolysis hallmark pathway was significantly enriched in high-LMS group and three distinct glycolysis-lactate patterns were generated. Patients in Cluster1 exhibited unfavorable outcomes and might be insensitive to immunotherapy. Glycolysis-lactate score was constructed for predicting prognosis with high accuracy and validated in external cohorts. Gene signature was developed and this signature was elevated in epithelial cells especially in tumor mass on single-cell level. Finally, we found that the glycolysis-lactate signature levels were consistent with the malignancy of histological subtypes.

Discussion

Our study demonstrated that an 18-microbe prognostic score and a 19-gene glycolysis-lactate signature for predicting prognosis of LUAD patients. Our LMS, glycolysis-lactate score and glycolysis-lactate signature have potential roles in precision therapy of LUAD patients.

Multi-Omics Reveals the Impact of Exogenous Short-Chain Fatty Acid Infusion on Rumen Homeostasis: Insights into Crosstalk between the Microbiome and the Epithelium in a Goat Model

Emerging data have underscored the significance of exogenous supplementation of butyrate in the regulation of rumen development and homeostasis. However, the effects of other short-chain fatty acids (SCFAs), such as acetate or propionate, has received comparatively less attention, and the consequences of extensive exogenous SCFA infusion remain largely unknown. In our study, we conducted a comprehensive investigation by infusion of three SCFAs to examine their respective roles in regulating the rumen microbiome, metabolism, and epithelium homeostasis. Data demonstrated that the infusion of sodium acetate (SA) increased rumen index while also promoting SCFA production and absorption through the upregulation of SCFA synthetic enzymes and the mRNA expression of SLC9A1 gene. Moreover, both SA and sodium propionate infusion resulted in an enhanced total antioxidant capacity, an increased concentration of occludin, and higher abundances of specific rumen bacteria, such as "Candidatus Saccharimonas," Christensenellaceae R-7, Butyrivibrio, Rikenellaceae RC9 gut, and Alloprevotella. In addition, sodium butyrate (SB) infusion exhibited positive effects by increasing the width of rumen papilla and the thickness of the stratum basale. SB infusion further enhanced antioxidant capacity and barrier function facilitated by cross talk with Monoglobus and Incertae Sedis. Furthermore, metabolome and transcriptome data revealed distinct metabolic patterns in rumen contents and epithelium, with a particular impact on amino acid and fatty acid metabolism processes. In conclusion, our data provided novel insights into the regulator effects of extensive infusion of the three major SCFAs on rumen fermentation patterns, antioxidant capacity, rumen barrier function, and rumen papilla development, all achieved without inducing rumen epithelial inflammation. IMPORTANCE The consequences of massive exogenous supplementation of SCFAs on rumen microbial fermentation and rumen epithelium health remain an area that requires further exploration. In our study, we sought to investigate the specific impact of administering high doses of exogenous acetate, propionate, and butyrate on rumen homeostasis, with a particular focus on understanding the interaction between the rumen microbiome and epithelium. Importantly, our findings indicated that the massive infusion of these SCFAs did not induce rumen inflammation. Instead, we observed enhancements in antioxidant capacity, strengthening of rumen barrier function, and promotion of rumen papilla development, which were facilitated through interactions with specific rumen bacteria. By addressing existing knowledge gaps and offering critical insights into the regulation of rumen health through SCFA supplementation, our study holds significant implications for enhancing the well-being and productivity of ruminant animals.

Weighted gene coexpression network analysis and machine learning reveal oncogenome associated microbiome plays an important role in tumor immunity and prognosis in pan-cancer

BACKGROUND

For many years, the role of the microbiome in tumor progression, particularly the tumor microbiome, was largely overlooked. The connection between the tumor microbiome and the tumor genome still requires further investigation.

METHODS

The TCGA microbiome and genome data were obtained from Haziza et al.'s article and UCSC Xena database, respectively. Separate WGCNA networks were constructed for the tumor microbiome and genomic data after filtering the datasets. Correlation analysis between the microbial and mRNA modules was conducted to identify oncogenome associated microbiome module (OAM) modules, with three microbial modules selected for each tumor type. Reactome analysis was used to enrich biological processes. Machine learning techniques were implemented to explore the tumor type-specific enrichment and prognostic value of OAM, as well as the ability of the tumor microbiome to differentiate TP53 mutations.

RESULTS

We constructed a total of 182 tumor microbiome and 570 mRNA WGCNA modules. Our results show that there is a correlation between tumor microbiome and tumor genome. Gene enrichment analysis results suggest that the genes in the mRNA module with the highest correlation with the tumor microbiome group are mainly enriched in infection, transcriptional regulation by TP53 and antigen presentation. The correlation analysis of OAM with CD8+ T cells or TAM1 cells suggests the existence of many microbiota that may be involved in tumor immune suppression or promotion, such as Williamsia in breast cancer, Biostraticola in stomach cancer, Megasphaera in cervical cancer and Lottiidibacillus in ovarian cancer. In addition, the results show that the microbiome-genome prognostic model has good predictive value for short-term prognosis. The analysis of tumor TP53 mutations shows that tumor microbiota has a certain ability to distinguish TP53 mutations, with an AUROC value of 0.755. The tumor microbiota with high importance scores are Corallococcus, Bacillus and Saezia. Finally, we identified a potential anti-cancer microbiota, Tissierella, which has been shown to be associated with improved prognosis in tumors including breast cancer, lung adenocarcinoma and gastric cancer.

CONCLUSION

There is an association between the tumor microbiome and the tumor genome, and the existence of this association is not accidental and could change the landscape of tumor research.

Probiotic-Derived Bioactive Compounds in Colorectal Cancer Treatment

Colorectal cancer (CRC) is a multifactorial disease with increased morbidity and mortality rates globally. Despite advanced chemotherapeutic approaches for the treatment of CRC, low survival rates due to the regular occurrence of drug resistance and deleterious side effects render the need for alternative anticancer agents imperative. Accumulating evidence supports that gut microbiota imbalance precedes the establishment of carcinogenesis, subsequently contributing to cancer progression and response to anticancer therapy. Manipulation of the gut microbiota composition via the administration of probiotic-derived bioactive compounds has gradually attained the interest of scientific communities as a novel therapeutic strategy for CRC. These compounds encompass miscellaneous metabolic secreted products of probiotics, including bacteriocins, short-chain fatty acids (SCFAs), lactate, exopolysaccharides (EPSs), biosurfactants, and bacterial peptides, with profound anti-inflammatory and antiproliferative properties. This review provides a classification of postbiotic types and a comprehensive summary of the current state of research on their biological role against CRC. It also describes how their intricate interaction with the gut microbiota regulates the proper function of the intestinal barrier, thus eliminating gut dysbiosis and CRC development. Finally, it discusses the future perspectives in precision-medicine approaches as well as the challenges of their synthesis and optimization of administration in clinical studies.

A narrative review on the use of probiotics in several diseases. Evidence and perspectives

Gut microbiota is a complex ecosystem, strictly linked to health and disease, as a balanced composition (referred as eubiosis) is necessary for several physiological functions, while an unbalanced composition (dysbiosis) is often associated to pathological conditions and/or diseases. An altered microbiota could be positively affected and partially restored through probiotic supplementation, among others. This review addresses the effects of probiotics in several conditions, used as case-studies (colorectal cancer, neuro-psychiatric diseases, intestinal diseases, obesity, diabetes, metabolic syndrome, immune system, and musculoskeletal system disorders) by pointing out the clinical outcomes, the mode of action, mainly related to the production of short chain fatty acids (SCFA), the impact of probiotic dose and mode of supplementation, as well as trying to highlight a hit of the most used genera.

Alterations in the gut microbiota and the efficacy of adjuvant probiotic therapy in liver cirrhosis

Background

Liver cirrhosis is the end stage of various chronic liver diseases (CLDs). The gut microbiota can impact the liver environment and trigger chronic liver inflammation through the gut-liver axis. Alteration of the gut microbiota has become an effective strategy in the biological treatment of cirrhosis.

Methods

Twenty-eight patients with liver cirrhosis and 16 healthy individuals were included, and fresh stool samples were collected. We analyzed changes in the gut microbiota between groups by 16S rRNA sequencing and evaluated the association between microbiota alterations and hepatic function. Additionally, 102 cirrhotic patients were retrospectively enrolled and divided into a probiotic group (n=44) and a nonprobiotic group (n=58) in addition to standard treatment for cirrhosis. Patients were monitored for hematological parameters and hepatic function during the six-month follow-up.

Results

The gut microbiota profile of patients with cirrhosis was greatly different from that of healthy individuals, presenting with significantly reduced α diversity and decreased abundance of representative SCFA-producing bacteria including Firmicutes, Coprococcus and Clostridium IV. The pathogenic bacteria Gammaproteobacteria, Veillonella, and Bacilli were greatly enriched in cirrhotic patients. Additionally, patients with decompensated cirrhosis (DCPC) had a significantly reduced abundance of Oscillibacter compared to compensated cirrhosis (CPC), which is also a SCFA-producing bacteria, and the lower Firmicutes to Bacteroidetes ratio and enhanced MDR values were also shown in DCPC patients compared to CPC patients. In addition, the abundance of Firmicutes was negatively related to hepatic function in cirrhotic patients, including the levels of ALT, AST, and DBIL. From the retrospective study, we found that biochemical improvements in alanine transaminase (ALT) and total bilirubin (TBIL) were obtained in DCPC patients who received oral probiotic therapy compared with the nonprobiotic group.

Conclusion

Severe microbial dysbiosis existed in patients with liver cirrhosis, especially patients who reached the decompensatory stage. SCFA-producing bacteria were significantly reduced in cirrhosis. Altered gut microbiota cause changes in functional modules, which may contribute to cirrhosis progression and are associated with clinical prognosis. Adjuvant probiotic supplementation to enhance SCFA-producing bacteria can be a prospective therapy for patients with cirrhosis.

Characteristics of glucose and lipid metabolism and the interaction between gut microbiota and colonic mucosal immunity in pigs during cold exposure

BACKGROUND

Cold regions have long autumn and winter seasons and low ambient temperatures. When pigs are unable to adjust to the cold, oxidative damage and inflammation may develop. However, the differences between cold and non-cold adaptation regarding glucose and lipid metabolism, gut microbiota and colonic mucosal immunological features in pigs are unknown. This study revealed the glucose and lipid metabolic responses and the dual role of gut microbiota in pigs during cold and non-cold adaptation. Moreover, the regulatory effects of dietary glucose supplements on glucose and lipid metabolism and the colonic mucosal barrier were evaluated in cold-exposed pigs.

RESULTS

Cold and non-cold-adapted models were established by Min and Yorkshire pigs. Our results exhibited that cold exposure induced glucose overconsumption in non-cold-adapted pig models (Yorkshire pigs), decreasing plasma glucose concentrations. In this case, cold exposure enhanced the ATGL and CPT-1α expression to promote liver lipolysis and fatty acid oxidation. Meanwhile, the two probiotics (Collinsella and Bifidobacterium) depletion and the enrichment of two pathogens (Sutterella and Escherichia-Shigella) in colonic microbiota are not conducive to colonic mucosal immunity. However, glucagon-mediated hepatic glycogenolysis in cold-adapted pig models (Min pigs) maintained the stability of glucose homeostasis during cold exposure. It contributed to the gut microbiota (including the enrichment of the Rikenellaceae RC9 gut group, [Eubacterium] coprostanoligenes group and WCHB1-41) that favored cold-adapted metabolism.

CONCLUSIONS

The results of both models indicate that the gut microbiota during cold adaptation contributes to the protection of the colonic mucosa. During non-cold adaptation, cold-induced glucose overconsumption promotes thermogenesis through lipolysis, but interferes with the gut microbiome and colonic mucosal immunity. Furthermore, glucagon-mediated hepatic glycogenolysis contributes to glucose homeostasis during cold exposure.

Probiotics: functional food ingredients with the potential to reduce hypertension

Hypertension is an increasingly pressing public health concern across the globe. It can be triggered by a variety of factors such as age and diet, as well as the stress of modern life. The traditional treatment of hypertension includes calcium ion blockers, angiotensin II receptor inhibitors and β-receptor blockers, but these drugs have at least some side effects. Recent studies have revealed that intestinal flora plays a vital role in maintaining and promoting human health. This is due to the type and amount of probiotics present in the flora. Probiotics can reduce hypertension symptoms through four mechanisms: regulating vascular oxidative stress, producing short-chain fatty acids, restoring endothelial cell function, and reducing inflammation. It has been reported that certain functional foods, using probiotics as their raw material, can modify the composition of intestinal flora, thus regulating hypertension symptoms. Consequently, utilizing the probiotic function of probiotics in conjunction with the properties of functional foods to treat hypertension is a novel, side-effect-free treatment method. This study seeks to summarize the various factors that contribute to hypertension, the mechanism of probiotics in mitigating hypertension, and the fermented functional foods with probiotic strains, in order to provide a basis for the development of functional foods which utilize probiotics as their raw material and may have the potential to reduce hypertension.

New Insights and Potential Therapeutic Interventions in Metabolic Diseases

Endocrine homeostasis and metabolic diseases have been the subject of extensive research in recent years. The development of new techniques and insights has led to a deeper understanding of the mechanisms underlying these conditions and opened up new avenues for diagnosis and treatment. In this review, we discussed the rise of metabolic diseases, especially in Western countries, the genetical, psychological, and behavioral basis of metabolic diseases, the role of nutrition and physical activity in the development of metabolic diseases, the role of single-cell transcriptomics, gut microbiota, epigenetics, advanced imaging techniques, and cell-based therapies in metabolic diseases. Finally, practical applications derived from this information are made.

The Gut Microbial Bile Acid Modulation and Its Relevance to Digestive Health and Diseases

The human gut microbiome has been linked to numerous digestive disorders, but its metabolic products have been much less well characterized, in part due to the expense of untargeted metabolomics and lack of ability to process the data. In this review, we focused on the rapidly expanding information about the bile acid repertoire produced by the gut microbiome, including the impacts of bile acids on a wide range of host physiological processes and diseases, and discussed the role of short-chain fatty acids and other important gut microbiome-derived metabolites. Of particular note is the action of gut microbiome-derived metabolites throughout the body, which impact processes ranging from obesity to aging to disorders traditionally thought of as diseases of the nervous system, but that are now recognized as being strongly influenced by the gut microbiome and the metabolites it produces. We also highlighted the emerging role for modifying the gut microbiome to improve health or to treat disease, including the "engineered native bacteria'' approach that takes bacterial strains from a patient, modifies them to alter metabolism, and reintroduces them. Taken together, study of the metabolites derived from the gut microbiome provided insights into a wide range of physiological and pathophysiological processes, and has substantial potential for new approaches to diagnostics and therapeutics of disease of, or involving, the gastrointestinal tract.

Equivalent carbon number based targeted odd chain fatty acyl lipidomics reveals triacylglycerol profiling in clinical colon cancer

Odd chain fatty acids (OCFAs) present in very low level at nearly 1% of total fatty acids in human plasma and thus their functions were usually ignored. Recent epidemiological studies have shown that OCFAs are inversely associated with a variety of disease risks. However, the contribution of OCFAs incorporated into complex lipids remains elusive. Here, we developed a targeted odd chain fatty acyl containing lipidomics method based on equivalent carbon number and retention time prediction. The method displayed good reproducibility and robustness as shown by peak width at half height within 0.7 min and coefficient of variation (CV) under 20%. A total number of 776 lipid species with odd chain fatty acyl residues could be detected in the electrospray ionization (ESI) mode of reverse phase liquid chromatography-mass spectrometry, of which 309 lipids were further validated using multiple MRM transitiions. Using this method, we quantified odd chain fatty acyl containing lipidome in tissues from 12 colon cancer patients, revealing the remodeling of triacylglycerol (TAG). The dynamics of odd chain fatty acyl lipids were further consolidated by the association with genomic and proteomic feature of altered catabolism of branched chain amino acids and TAG endogenous synthesis in colon cancer. This lipidomics approach will be applicable for screening of dysregulated odd chain fatty acyl lipids, which enriches and improves the methods for diagnosis and prognosis evaluation of cancer using lipidomics.

How the interplay among the tumor microenvironment and the gut microbiota influences the stemness of colorectal cancer cells

Colorectal cancer (CRC) remains the third most prevalent cancer disease and involves a multi-step process in which intestinal cells acquire malignant characteristics. It is well established that the appearance of distal metastasis in CRC patients is the cause of a poor prognosis and treatment failure. Nevertheless, in the last decades, CRC aggressiveness and progression have been attributed to a specific cell population called CRC stem cells (CCSC) with features like tumor initiation capacity, self-renewal capacity, and acquired multidrug resistance. Emerging data highlight the concept of this cell subtype as a plastic entity that has a dynamic status and can be originated from different types of cells through genetic and epigenetic changes. These alterations are modulated by complex and dynamic crosstalk with environmental factors by paracrine signaling. It is known that in the tumor niche, different cell types, structures, and biomolecules coexist and interact with cancer cells favoring cancer growth and development. Together, these components constitute the tumor microenvironment (TME). Most recently, researchers have also deepened the influence of the complex variety of microorganisms that inhabit the intestinal mucosa, collectively known as gut microbiota, on CRC. Both TME and microorganisms participate in inflammatory processes that can drive the initiation and evolution of CRC. Since in the last decade, crucial advances have been made concerning to the synergistic interaction among the TME and gut microorganisms that condition the identity of CCSC, the data exposed in this review could provide valuable insights into the biology of CRC and the development of new targeted therapies.

Immuno-oncology-microbiome axis of gastrointestinal malignancy

Research on the relationship between the microbiome and cancer has been controversial for centuries. Recent works have discovered that the intratumor microbiome is an important component of the tumor microenvironment (TME). Intratumor bacteria, the most studied intratumor microbiome, are mainly localized in tumor cells and immune cells. As the largest bacterial reservoir in human body, the gut microbiome may be one of the sources of the intratumor microbiome in gastrointestinal malignancies. An increasing number of studies have shown that the gut and intratumor microbiome play an important role in regulating the immune tone of tumors. Moreover, it has been recently proposed that the gut and intratumor microbiome can influence tumor progression by modulating host metabolism and the immune and immune tone of the TME, which is defined as the immuno-oncology-microbiome (IOM) axis. The proposal of the IOM axis provides a new target for the tumor microbiome and tumor immunity. This review aims to reveal the mechanism and progress of the gut and intratumor microbiome in gastrointestinal malignancies such as esophageal cancer, gastric cancer, liver cancer, colorectal cancer and pancreatic cancer by exploring the IOM axis. Providing new insights into the research related to gastrointestinal malignancies.

Short-Chain Fatty-Acid-Producing Bacteria: Key Components of the Human Gut Microbiota

Short-chain fatty acids (SCFAs) play a key role in health and disease, as they regulate gut homeostasis and their deficiency is involved in the pathogenesis of several disorders, including inflammatory bowel diseases, colorectal cancer, and cardiometabolic disorders. SCFAs are metabolites of specific bacterial taxa of the human gut microbiota, and their production is influenced by specific foods or food supplements, mainly prebiotics, by the direct fostering of these taxa. This Review provides an overview of SCFAs' roles and functions, and of SCFA-producing bacteria, from their microbiological characteristics and taxonomy to the biochemical process that lead to the release of SCFAs. Moreover, we will describe the potential therapeutic approaches to boost the levels of SCFAs in the human gut and treat different related diseases.

Long-term effect of Helicobacter pylori eradication on colorectal cancer incidences

Background

There is evidence supporting the association between Helicobacter pylori infection and colorectal cancer (CRC), but whether H. pylori eradication reduces the risk of CRC is still unknown.

Objectives

To compare the incidence of CRC in subjects who had received H. pylori eradication therapy with general population.

Design

A population-based retrospective cohort study.

Methods

This study included all H. pylori-infected subjects who had received their first course of clarithromycin-containing triple therapy in 2003-2015 in Hong Kong. We compared the observed incidences of CRC in this H. pylori eradicated cohort with the expected incidences in the age- and sex-matched general population. The standardized incidence ratio (SIR) with 95% confidence interval (CI) was computed.

Results

Among 96,572 H. pylori-eradicated subjects with a median follow-up of 9.7 years, 1417 (1.5%) developed CRC. Primary analysis showed no significant difference in the observed and expected incidences of CRC (SIR: 1.03, 95% CI: 0.97-1.09). However, when stratified according to the follow-up period, higher incidence of CRC was only observed in the first 5 years after eradication (SIR: 1.47, 95% CI: 1.39-1.55), but it was lower (SIR: 0.85, 95% CI: 0.74-0.99) than general population after 11 years. When stratified by tumor location, the observed incidence was higher for colon (SIR: 1.20, 95% CI: 1.12-1.29) but lower for rectal cancer (SIR: 0.90, 95% CI: 0.81-0.999) among H. pylori-eradicated subjects.

Conclusions

H. pylori-infected subjects appeared to have a higher incidence of CRC initially, which declined progressively to a level lower than general population 10 years after H. pylori eradication, particularly for rectal cancer.

Multi-omics analysis revealed NMBA induced esophageal carcinoma tumorigenesis via regulating PPARα signaling pathway

As widespread environmental carcinogens causing esophageal carcinoma (EC), the effects of N-nitrosamines on human health hazards and accurate toxicity mechanisms have not been well-elucidated. In this study, we explored the tumorigenic mechanism of N-nitrosomethylbenzylamine (NMBA) exposure using both cell and rat models. It was found that NMBA (2 μM) exposure for 26 weeks induced malignant transformation of normal esophageal epithelial (Het-1A) cells. After then proteomics analysis showed that lipid metabolism disorder predominantly participated in the process of NMBA-induced cell malignant transformation. Further the integrated proteomics and lipidomics analysis revealed that the enhancement of fatty acid metabolism promoted the EC tumorigenesis induced by NMBA through facilitating the fatty acid-associated PPARα signaling pathway. The animal studies also revealed that accelerated fatty acid decomposition in the progression of NMBA-induced EC models of rats was accompanied by the activation of the PPARα pathway. Overall, our findings depicted the key dynamic molecular alteration triggered by N-nitrosamines, and provided comprehensive biological perspectives into the carcinogenic risk assessment of N-nitrosamines.

Obesity, but not high-fat diet, is associated with bone loss that is reversed via CD4+CD25+Foxp3+ Tregs-mediated gut microbiome of non-obese mice

Osteoporosis is characterized by decreased bone mass, microarchitectural deterioration, and increased bone fragility. High-fat diet (HFD)-induced obesity also results in bone loss, which is associated with an imbalanced gut microbiome. However, whether HFD-induced obesity or HFD itself promotes osteoclastogenesis and consequent bone loss remains unclear. In this study, we developed HFD-induced obesity (HIO) and non-obesity (NO) mouse models to evaluate the effect of HFD on bone loss. NO mice were defined as body weight within 5% of higher or lower than that of chow diet fed mice after 10 weeks HFD feeding. NO was protected from HIO-induced bone loss by the RANKL /OPG system, with associated increases in the tibia tenacity, cortical bone mean density, bone volume of cancellous bone, and trabecular number. This led to increased bone strength and improved bone microstructure via the microbiome-short-chain fatty acids (SCFAs) regulation. Additionally, endogenous gut-SCFAs produced by the NO mice activated free fatty acid receptor 2 and inhibited histone deacetylases, resulting in the promotion of Treg cell proliferation in the HFD-fed NO mice; thereby, inhibiting osteoclastogenesis, which can be transplanted by fecal microbiome. Furthermore, T cells from NO mice retain differentiation of osteoclast precursors of RAW 264.7 macrophages ex vivo. Our data reveal that HFD is not a deleterious diet; however, the induction of obesity serves as a key trigger of bone loss that can be blocked by a NO mouse-specific gut microbiome.

The Effect of Exercise Prescription on the Human Gut Microbiota and Comparison between Clinical and Apparently Healthy Populations: A Systematic Review

This study systematically reviewed all human longitudinal exercise interventions that reported changes in the gut microbiota; frequency, intensity, duration and type of exercise were assessed to determine the influence of these variables on changes to the gut microbiota in both healthy individuals and clinical populations (PROPERO registration: CRD42022309854). Using PRISMA guidelines, trials analysing gut microbiota change with exercise interventions were included independent of trial randomisation, population, trial duration or analysis technique. Studies were excluded when microbiota abundance was not reported or when exercise was combined with other interventions. Twenty-eight trials were included, of which twelve involved healthy populations only and sixteen involved mixed or clinical-only populations. The findings show that participation in exercise of moderate to high-intensity for 30-90 min ≥3 times per week (or between 150-270 min per week) for ≥8 weeks is likely to produce changes in the gut microbiota. Exercise appears to be effective in modifying the gut microbiota in both clinical and healthy populations. A more robust methodology is needed in future studies to improve the certainty of the evidence.

Role of Dietary Defatted Rice Bran in the Modulation of Gut Microbiota in AOM/DSS-Induced Colitis-Associated Colorectal Cancer Rat Model

Defatted rice bran (DRB) is a by-product of rice bran derived after the oil extraction. DRB contains several bioactive compounds, including dietary fiber and phytochemicals. The supplementation with DRB manifests chemopreventive effects in terms of anti-chronic inflammation, anti-cell proliferation, and anti-tumorigenesis in the azoxymethane (AOM) and dextran sodium sulfate (DSS)-induced colitis-associated colorectal cancer (CRC) model in rats. However, little is known about its effect on gut microbiota. Herein, we investigated the effect of DRB on gut microbiota and short chain fatty acid (SCFA) production, colonic goblet cell loss, and mucus layer thickness in the AOM/DSS-induced colitis-associated CRC rat model. The results suggested that DRB enhanced the production of beneficial bacteria (Alloprevotella, Prevotellaceae UCG-001, Ruminococcus, Roseburia, Butyricicoccus) and lessened the production of harmful bacteria (Turicibacter, Clostridium sensu stricto 1, Escherichia-Shigella, Citrobacter) present in colonic feces, mucosa, and tumors. In addition, DRB also assisted the cecal SCFAs (acetate, propionate, butyrate) production. Furthermore, DRB restored goblet cell loss and improved the thickness of the mucus layer in colonic tissue. These findings suggested that DRB could be used as a prebiotic supplement to modulate gut microbiota dysbiosis, which decreases the risks of CRC, therefore encouraging further research on the utilization of DRB in various nutritional health products to promote the health-beneficial bacteria in the colon.

Modulation of the Tumor Microenvironment by Microbiota-Derived Short-Chain Fatty Acids: Impact in Colorectal Cancer Therapy

Finding new therapeutic approaches towards colorectal cancer (CRC) is of increased relevance, as CRC is one of the most common cancers worldwide. CRC standard therapy includes surgery, chemotherapy, and radiotherapy, which may be used alone or in combination. The reported side effects and acquired resistance associated with these strategies lead to an increasing need to search for new therapies with better efficacy and less toxicity. Several studies have demonstrated the antitumorigenic properties of microbiota-derived short-chain fatty acids (SCFAs). The tumor microenvironment is composed by non-cellular components, microbiota, and a great diversity of cells, such as immune cells. The influence of SCFAs on the different constituents of the tumor microenvironment is an important issue that should be taken into consideration, and to the best of our knowledge there is a lack of reviews on this subject. The tumor microenvironment is not only closely related to the growth and development of CRC but also affects the treatment and prognosis of the patients. Immunotherapy has emerged as a new hope, but, in CRC, it was found that only a small percentage of patients benefit from this treatment being closely dependent on the genetic background of the tumors. The aim of this review was to perform an up-to-date critical literature review on current knowledge regarding the effects of microbiota-derived SCFAs in the tumor microenvironment, particularly in the context of CRC and its impact in CRC therapeutic strategies. SCFAs, namely acetate, butyrate, and propionate, have the ability to modulate the tumor microenvironment in distinct ways. SCFAs promote immune cell differentiation, downregulate the expression of pro-inflammatory mediators, and restrict the tumor-induced angiogenesis. SCFAs also sustain the integrity of basement membranes and modulate the intestinal pH. CRC patients have lower concentrations of SCFAs than healthy individuals. Increasing the production of SCFAs through the manipulation of the gut microbiota could constitute an important therapeutic strategy towards CRC due to their antitumorigenic effect and ability of modulating tumor microenvironment.